Lawyers for Robert F Kennedy’s killer Sirhan Sirhan claim to have new evidence that will free him from prison, 42 years after he was jailed for assassinating the US senator.

They say the new material hands them “game, set and match” in their campaign to release him from the life sentence he was given on being convicted for gunning down the senator at a California hotel.

They have launched a fresh appeal on behalf of Sirhan, 67, claiming in court for the first time that prosecutors fabricated ballistics evidence against him at trial, switching a bullet that was taken from the dead senator’s neck for one that they claimed matched the defendant’s gun.

Lawyers also seek a re-examination of claims that Sirhan was framed by shadowy agents – indirectly suggested as being the CIA – who they say “hypno-programmed” him into taking part in the shooting to divert attention from their own fatal gunfire.

Court documents filed in federal court in Los Angeles now pull together years of research, evidentiary documents and psychological analyses of Sirhan for a case that his lawyer says proves him as a victim of “an egregious miscarriage of justice” and “horrendous violations” of his legal rights.

“On the law, and on the evidence, it’s game set and match to us. It’s all over,” Dr William Pepper told The Sunday Telegraph.